#include<stdio.h>
int main()
{
    int a,i,b,n;
    printf("There are following friendly -numbers pair samller than 3000:\n");
    for(a=1;a<=3000;a++){
        for(b=0,i=1;i<=a/2;i++)
        if(!(a%i))b+=i;
        for(n=0,i=1;i<=b/2;i++)
        if(!(n%i)) n+=i;
        if(n==a&&a<b)
        printf(" %4d..%4d",a,b);
    }
}